Ovarian cancer is the fifth most leading cause of cancer related deaths in women in the US. It has been observed that the cancer relapses within relatively short periods of time even after the surgery and chemotherapy. Therefore, immunotherapeutic strategies may serve as an alternative to control the recurrence or progression of ovarian cancer. Oral vaccines are relatively easy to administer. However, the degradation of the antigenic component of the vaccine in the gastro-intestinal tract is a major problem. In this research study, we will formulate and evaluate the efficacy of oral ovarian cancer nanoparticulate vaccine in mice to prevent/retard the ovarian cancer growth. The antigenic material for the vaccine will be prepared from ID8 murine ovarian cancer cells as this cell line correlates well with human ovarian cancer cell lines in terms of various similar markers and provides a unique model to study ovarian cancer progression and pre-therapeutic trials in mice with intact immune systems. In this proposal, ovarian cancer antigens, M-cell targeting ligands, immuno-stimulatory cytokines and toll-like receptor (TLR9) ligands such as CpG oligonucleotide that can induce T-cell responses, will be encapsulated into nanoparticles made up of a biodegradable and biocompatible polymer matrix containing a mixture of an enteric polymer to prevent their degradation under acidic conditions in the stomach and also a sustained release polymer enabling the release of the antigen in a controlled manner. These vaccine nanoparticles will be administered to female C57BL/6 mice with ovarian tumors by the oral route. These particles are targeted to M-cells present in Peyer's patches in the intestine, which take up the encapsulated vaccine to generate immunity by presenting the antigen to dendritic cells and macrophages. Serum samples will be obtained to determine the antigen specific IgG levels to assess the systemic immunity. We will also carry out mechanistic studies to investigate the role of CD+ T-cells, CD8+ T-cells, NK cells, and B cells in anti-tumor immunity induced by the oral vaccines. We will also evaluate the efficacy of the vaccine microparticles after a) including M-cell inducing RANKL b) Treg depletion studies with low dose of cyclophosphamide or anti-CD25 Ab in order to evaluate immunotolerance in pre-existing tumor models and c) adoptive transfer of T-cells. Long-term memory responses of the vaccine will also be assessed since this is a necessary component of a successful vaccine. Recently, major advances have been made in the formulation methodology at the Nanotechnology Laboratory allowing us to produce nanoparticles using the spray drying methodology in a single step process. This is a major advantage from the standpoint of advancing the vaccine formulation from bench to clinic as scale-up of this process can be achieved with no further modifications.